Rear-end crashes are one of the most common crash types. Passenger cars involved in rear-end crashes frequently produce severe outcomes. However, no study investigated the differences in the injury severity of occupant groups when cars are involved as following and leading vehicles in rear-end crashes. Therefore, the focus of this investigation is to compare the key factors affecting the injury severity between the front- and rear-car occupant groups in rear-end crashes. First, data is extracted from the Fatality Analysis Reporting System (FARS) for two types of rear-end crashes from 2017 to 2019, including passenger cars as rear-end and rear-ended vehicles. Significant injury severity difference between front- and rear-car occupant groups is found by conducting likelihood ratio test. Moreover, the front- and rear-car occupant groups are modelled by the correlated random parameter logit model with heterogeneity in means (CRPLHM) and the random parameter logit model with heterogeneity in means (RPLHM), respectively. From the modeling, the significant factors are occupant positions, driver age, overturn, vehicle type, etc. For instance, the driving and front-right positions significantly increase the probability of severe injury when struck by another vehicle. Large truck-strike-car tends to cause severe outcomes compared to car-strike-large truck. This study provides an insightful knowledge of mechanism of occupant injury severity in rear-end crashes, and propose some effective countermeasures to mitigate the crash severity, such as implementing stricter seat belt laws, improving the coverage of the streetlights, strengthening car driver's emergency response ability.

翻译：追尾碰撞是最常见的事故类型之一。参与追尾事故的乘用车经常导致严重后果。然而，尚无研究探讨当乘用车在追尾事故中分别作为前车和后车时，不同乘员群体损伤严重性的差异。因此，本研究的重点是比较追尾事故中前车与后车乘员群体损伤严重性的关键影响因素。首先，从2017年至2019年的死亡分析报告系统（FARS）中提取两类追尾事故数据，包括作为追尾车辆和被追尾车辆的情形。通过似然比检验发现前车与后车乘员群体之间存在显著的损伤严重性差异。此外，分别采用均值异质性相关随机参数Logit模型（CRPLHM）和均值异质性随机参数Logit模型（RPLHM）对前车与后车乘员群体进行建模。建模结果表明，显著影响因素包括乘员位置、驾驶员年龄、翻车、车辆类型等。例如，当被其他车辆撞击时，驾驶员位和右前乘员位显著增加了重伤概率；大型卡车撞击乘用车比乘用车撞击大型卡车更易导致严重后果。本研究揭示了追尾事故中乘员损伤严重性的内在机制，并提出了一些有效缓解事故严重性的对策，如实施更严格的安全带法规、提高路灯覆盖率、加强汽车驾驶员应急反应能力。